Motorcycle radiator

ABSTRACT

A heat exchange device for mounting between the front fork and the engine of a motorcycle comprises two vertical coolant outflow tanks on either side of a core area, and a coolant inflow tank located midway between the outflow tanks and connected to the latter. The lower part of the device comprises a series of bent tubes having cooling fins therebetween, to form an inverted U-shaped space which straddles the top of the engine, so as to provide sufficient clearance to accommodate the expansion and contraction strokes of the front fork.

SUMMARY OF THE INVENTION

The present invention relates to a heat exchange device to be mountedbetween the front fork and the engine of a motorcycle, and which has alower escape section in the shape of an inverted U, formed of a seriesof bent tubes, providing a space for mounting the device so that itstraddles the engine, and leaves enough clearance for the expansion andcontraction strokes of the front fork.

BACKGROUND OF THE INVENTION

In motorcycles having water cooled engines, the space for accommodationof a radiator is rather limited, for reasons not only of dimensions, butalso of cooling capacity, external appearance, and other considerations.Generally, the radiator is positioned between the front fork supportingthe front wheel and the power unit of the engine supported by themotorcycle frame, and is fixed to the upper portion of the latter. Theradiator normally comprises a core between two tanks for coolant inflowand coolant outflow, respectively. Within the core there are a number oftubes extending in various directions, forming a coolant circuitconnecting the tanks, and fins to expand the cooling surface area arearranged between these tubes. Hoses connect the tanks to the coolantinlet and outlet of the engine, respectively. The radiator has agenerally square cross section, and is somewhat wider than it is high.In order to increase the heat release effect, the heat release surfacearea is made as large as possible, and for reasons of appearance,especially in the case of motorcycles, the device preferably has avertically elongated shape.

However, particularly in the case of V-type engine motorcycles, becausethe upper portion of the engine protrudes in front of the frame, thearea between the front fork and the engine (i.e., the space between thefront fender and the radiator) is narrow. Thus, if a verticallyelongated box type radiator is used, the expansion and contractionstrokes of the front fork cannot be properly accommodated. For thisreason, when this type of radiator is to be used, the space between thefront fork and the engine must be expanded, and a motorcycle with aV-type engine cannot be scaled down to a smaller size. On the otherhand, if the expansion of this space is to be avoided, it then becomesnecessary to obtain the required heat release surface area by designingthe radiator in a horizontally elongated form. The result of thisexpedient is to sacrifice the external appearance of the motorcycle,making it impossible to produce a motorcycle having a body which is slimand of narrow width.

OBJECT OF THE INVENTION

An object of the present invention is a heat exchanger for motorcycleswhich overcomes the above-noted drawbacks while yet providing an ampleheat release surface area.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more clearly understood, referencewill now be made to the accompanying drawings, in which severalembodiments of the invention are shown for purposes of illustration, andin which:

FIG. 1 is a side view of a motorcycle with a V-type engine, providedwith a radiator according to the prior art.

FIG. 2 is a perspective view, partly schematic, showing theconfiguration of such prior art radiator.

FIG. 3 is a perspective view similar to FIG. 2, also partly schematic,showing the configuration of the radiator according to the presentinvention.

FIG. 4 is a front view generally corresponding to FIG. 3, showing theradiator according to the present invention in relation to the engine.

FIG. 5 is a perspective view similar to FIG. 3, showing anotherembodiment of the radiator according to the present invention.

FIG. 6 is a view of a motorcycle with the device according to thepresent invention installed thereon.

DESCRIPTION OF PREFERRED EMBODIMENT

In FIGS. 1 and 2, which relate to the prior art, the radiator 1 islocated between the front fork 2, supporting the front wheel, and thepower unit 5 of the engine 4, supported by the frame 3, and is fixed tothe upper area of the frame 3. This radiator 1 comprises a core 10, withhose 7a connected to the engine coolant outlet (not shown), with fins 9arranged to expand the surface area, between a number of tubes 8, invarious directions, forming a coolant circuit connecting tanks 7 and 7',with tank 7 used for coolant inflow from the engine 4, and tank 7' usedfor coolant outflow to the engine 4, by means of hose 7'a connected toit and to the engine 4 coolant inlet (not shown). The body as a whole isin the form of a square box, somewhat wider than high. In order toincrease the heat release effect for the radiator, the heat releasesurface area is made as large as possible, and, in terms of the externalappearance of a motorcycle, the object preferably has a verticallyelongated shape.

As will appear from FIG. 1, the top of the engine 4 sticks out in frontof the frame 3, so that the area between the front fork 2 and the engine4 (i.e., the space between the front fender 6 and the radiator 1) isnarrow. If a vertically elongated box type radiator 1 is used (shown inbroken lines), the full expansion and contraction strokes of the frontfork 2 cannot be properly accommodated. This makes it necessary toexpand the space between the front fork 2 and the engine 4, renderingdownsizing of motorcycles with a V-type engine impossible. Analternative approach is to obtain the necessary heat release surfacearea by giving radiator 1 a horizontally elongated form. In this case,the external appearance of the vehicle body must be sacrificed, and thisis undesirable because the market demands a motorcycle which has a slimbody and a narrow width.

The present invention overcomes these disadvantages by means of a heatexchange device having a form appropriate to a motorcycle and offeringan ample heat release effect, comprising two spaced tanks, with aconnecting core therebetween, and a third tank, respectively connectingwith the first two tanks, through the intermediary of the core, locatedat a predetermined position with respect to the core, so as to allowspace for an escape section open at the bottom, of generally invertedU-shape, located at the bottom of the said third tank.

As shown in FIGS. 3 and 4, the heat exchange device (hereafter calledthe radiator) 11 comprises a coolant inflow tank 16, coolant outflowtanks 17 and 17', and a core 20, connecting with tank 16, the body as awhole being in a vertically elongated form. Tank 16 has a long, thin,boxlike form, provided at the top, more or less in the center, with aneck 16a, with a removable pressure cap 16b fitted thereto to permitregulation of the pressure inside the tank, as well as to extract airmixed in with the coolant. To the neck 16a is also attached one end of ahose 16c, the other end of which is connected to coolant outlet 4a,placed in the water jacket (not shown) of the engine 4, this hose beingused for coolant inflow. Tanks 17 and 17' are arranged symmetrically ata predetermined distance on either side of tank 16, and are thinner andlonger than tank 16, and also in more or less boxlike form. At theirlower ends they have, respectively, hoses 17a and 17'a connected tothem, the other end of each hose being connected to coolant inlet 4b,placed in the water jacket of the engine 4, these hoses being used forcoolant outflow.

Core 20, on each side of tank 16, connects tanks 17 and 17', and alsocomprises a set number of flattened tubes 18, placed at predeterminedintervals and extending more or less perpendicular to the tanks, andcooling fins 19, arranged in radiating form distributed among the tubes18. Located below the top of central tank 16, or at the bottom of bothsides of it, but above the bottoms of tanks 16, 17 and 17', among thecore tubes 18 connecting the bottoms of tanks 16, 17 and 17', are eighttubes 18a-18d, and 18a'-18d'. As shown in FIG. 3, tubes 18a'-18d' arebent toward the bottom of tank 16, and these bends are symmetricallyarranged. Thus, by means of these bends, a generally inverted U-shapedspace 21 is formed. This space 21, for instance in the case of thepreviously mentioned radiator for use with a V-type engine, as shown inFIG. 4, should be big enough to be able to straddle the top 4c of theengine 4.

A radiator with this kind of structure may, for instance, be made ofaluminum. In comparison with the use of copper, this permits the tubethickness to be made greater with the same weight, so that bending canbe performed on the tubing more easily, and without damage to thetubing.

The coolant which is heated up from cooling the engine comes fromcoolant outlet 4a, and passes through hose 16c into the central tank 16,then through the tubes 18 of the core 20 on both sides of tank 16, andflows out to tanks 17 and 17'. As the coolant passes through the varioustubes 18 of the core 20, heat is discharged by means of the surfaces ofthe tubes 18 and by the fins 19, and, as will be discussed subsequently,when installed in the vehicle, there is an interaction with the coolingeffect as the vehicle moves through the air, and a heat discharge effecttakes place for the radiator 11. As for the coolant which has flowed outinto tanks 17 and 17', this coolant is returned to the water jacket ofthe engine 4 by means of a circuit made up of hoses 17a and 17'a, andcoolant inlet 4b, and it again carries out cooling of the engine 4. Insuch a case, due to the heating of the coolant by the engine 4, airbubbles may be produced. With the present design, the portion where itis particularly easy for the air bubbles to build up, namely, the top ofthe bent portions of the tubes, has no build-up of air bubbles becauseof the installation of the tank 16, the bubbles being expelled via tank16.

FIG. 5 is an illustration of another embodiment of a radiator accordingto the invention. In this case, the coolant inflow tank 27 and thecoolant outflow tank 27' are installed on either side of the core of theradiator 22. Coolant inflow hose 27a is connected to the upper portionof tank 27, and coolant outflow hose 27'a is connected to the lowerportion of tank 27', and, as shown in FIGS. 3 and 4 and discussed above,a tank 26 is connected in the approximate center of the core 20. On thetop of this central tank 26, there is fitted metal neck 26a, with cap26b fitted on it; neck 26a, by means of hose 26c, is connected to areserve tank (not shown). As for its other structure and function, theseare the same as with radiator 11 shown in FIG. 3.

Radiators with structures such as those of 11 and 22 are carried onmotorcycles with V-type engines in the manner shown in FIG. 6. I.e.,they are fastened to the frame 3 at set points, such as the upper areasof tanks 17 and 17', or 27 and 27'; and, by means of the space section21 at the bottoms of radiators 11 and 22, the top 4c of the engine 4 isstraddled (see FIG. 4). The two lower sides of the said radiators 11 or22 are placed close to the sides of power unit 5, at points 11a and 11b,or 22a and 22b (see FIGS. 3, 4 and 5). As a result, the distance betweenfront fender 6 and points 11a and 11b or 22a and 22b on the two lowersides of the radiators 11 or 22 is widened, and the stroke length offront fork 2 is fully accommodated. In addition, in the cases ofvehicles having other than V-type engines, since an escape space isformed for the front fender due to space 21, even if the distancebetween the engine and the front fork is made narrower, reducing thescale of the vehicle, it is possible to amply accommodate the front forkstroke. As a consequence, since the design according to the inventionprovides for an increase in the core surface area on both sides of thespace 21, it is possible to make the radiator as a whole proportionatelynarrower, making it suitable for motorcycles requiring a narrow and slimbody.

It goes without saying that the radiator according to the invention mayalso be used as a cooling device for other fluids, e.g., enginelubrication oil.

What is claimed is:
 1. Heat exchange device for mounting between thepower unit and the front fork of a motorcycle, said device comprising anopen space of generally inverted U shape in the bottom region of saiddevice, said space being formed by a plurality of tubes bent so as tojointly form said generally inverted U shape, said bent tubes beinglocated beneath a plurality of straight tubes and, together with saidstraight tubes, constituting the core of said device, whereby sufficientclearance is provided between the front fender of said motorcycle andsaid heat exchange device to accommodate the expansion and contractionstrokes of said front fork.
 2. Heat exchange device according to claim1, comprising two vertical coolant outflow tanks on either side of acore area, and a vertical coolant inflow tank midway between saidoutflow tanks and generally parallel thereto, the lower end of saidinflow tank terminating above the lower ends of said outflow tanks andsaid space, whereby said bent tubes are in a higher position relative tothe lower end of said inflow tank than relative to the lower ends ofsaid outflow tanks.
 3. Heat exchange device according to claim 1 or 2,wherein said device comprises a radiator for cooling engine watercoolant.
 4. Heat exchange device according to claim 1 or 2, wherein saiddevice comprises an oil cooler for cooling engine lubricating oil. 5.Heat exchange device according to claim 1 or 2, wherein the cylinders ofsaid power unit are distributed in a fore-and-aft arrangement, and saiddevice is arranged to straddle the forward cylinders.
 6. Heat exchangedevice according to claim 1 or 2, said device being made of aluminum. 7.Heat exchange device according to claim 1 or 2, wherein said space issufficient to avoid the front wheel of said motorcycle hitting saiddevice upon upward propulsion of the front wheel by which said frontfork is supported, causing contraction of the latter.